Production method of optical element and optical element

Abstract

A production method of an optical element, which is utilized in a pickup apparatus using a light source emitting light having wavelength of 380 nm to 420 nm and has a functional layer such as an anti-reflection film 60 formed on a molded portion 50 comprising a resin having an alicyclic structure, comprising steps of forming a first SiO layer 62 in the molded portion 50 by a vapor deposition process using SiO as an evaporation source and introducing O 2 gas under a predetermined pressure, forming a second SiO layer 64 on the first SiO layer by a vapor deposition process using SiO as an evaporation source and introducing O 2 gas under a pressure lower than the pressure used in forming the first SiO layer 62 , and oxidizing the first SiO layer 62 and the second SiO layer 64.

1 . A production method of an optical element, which is utilized in a pickup apparatus using a light source emitting light having a wavelength of 380 nm to 420 nm and has a functional layer formed on a molded portion comprising a resin having an alicyclic structure, comprising steps of
 forming a first SiO layer on the molded portion by a vapor deposition process using SiO as an evaporation source and introducing O 2  gas under a predetermined pressure,   forming a second SiO layer on the first SiO layer by a vapor deposition process using SiO as an evaporation source and introducing O 2  gas under a pressure lower than the pressure used in forming the first SiO layer, and   oxidizing the first SiO layer and the second SiO layer.   
     
     
         2 . The production method of the optical element of  claim 1 , wherein
 in the step of forming the first SiO layer, the pressure of the introduced O 2  gas is adjusted to be in the range of 1.5×10 −2  to 2.5×10 −2  Pa to make a refractive index of the first SiO layer in the range of 1.47 to 1.53, and a thickness of the first SiO layer is adjusted to be in the range of 10 to 50 nm; and   in the step of forming the second SiO layer, the pressure of the introduced O 2  gas is adjusted to be in the range of 5.0×10 −3  to 1.5×10 −2  Pa to make a refractive index of the second SiO layer in the range of 1.53 to 1.83, and a thickness of the second SiO layer is adjusted to be in the range of 190 to 5000 nm.   
     
     
         3 . The production method of the optical element of  claim 1 , wherein the step of oxidizing the first SiO layer and the second SiO layer comprises at least one of the following steps:
 holding the molded portion having the first SiO layer and the second SiO layer for 10 hours to 7 days under an ambience of temperature lower than 90° C. and of lower than 90% relative humidity;   subjecting the first SiO layer and the second SiO layer to an ion implanting process;   immersing the molded portion having the first SiO layer and the second SiO layer into water,   subjecting the first SiO layer and the second SiO layer to an oxygen plasma treating and   subjecting the first SiO layer and the second SiO layer to a radiation of ultraviolet light under an ambience of ozone.   
     
     
         4 . The production method of the optical element of  claim 1 , further comprising steps of:
 forming a third layer on the second SiO layer with a high refractive index material having a refractive index 1.61 or more, and   forming a fourth layer on the third layer with a low refractive index material having a refractive index less than 1.61.   
     
     
         5 . The production method of the optical element of  claim 4 , comprising a step of forming a fifth layer or more by repeating alternately laminating the layer formed with the high refractive index material and the layer formed with the low refractive index material. 
     
     
         6 . An optical element produced by the production method of  claim 1 .